Nice Little Add-On, This One ! Rated 5 out of 5 stars
Nice and useful to pimp Firefox a little bit.
I use it in my umpteen portable Test-Foxes too.
(There is a small compatibility issue with the not so vital "Add-on Compatibility Reporter (ACR) 1.1":
"ACR 1.1" enabled bears down most times after a firefox-newstart this innocent 'n' cute "App Button Clear" - then (by operating experience) I could if I would disable & reanimate once this mission-critical "A. B. Clear" to help it serve it's purpose. But - just to pay compensation to "A. B. Clear" - I prefere to sentence the "ACR 1.1" to everlasting disabling-penalty into the dark and rotten dungeon of the add-ons-manager! Don't need'm nor love'm, who may get him ? ;-))
'App Button Clear' lives forever